From the National Tropical Botanical Garden Digging into the past to find the future Palaeo-ecology meets restoration biology On both the north and south shores of odds posed by aggressive alien plants and DAVID A. BURNEY Kauai, NTBG has several exciting new animals has been that NTBG staff pay DIRECTOR OF CONSERVATION, restoration projects with ties to palaeo- close attention to ecological history in NATIONAL TROPICAL ecology and archaeobotany. These planning its restorative efforts. Hawaiian BOTANICAL GARDEN include a project along the coast fronting oral traditions, early historical accounts, the Allerton Garden, an area called Lawai and particularly information from archae- cological restoration projects in Kai, which was initiated by grants from ological and palaeo-ecological sites near the Hawaiian lowlands have little the US Fish & Wildlife Service and the the restorations have provided useful Eto go on in terms of intact Natural Resources Conservation Service evidence concerning the site’s potential coastal forest ecosystems to serve as (USDA). In the more inland parts of the for restoration, serving as reference models. Nevertheless, a program of Lawai Valley, NTBG’s McBryde Garden systems or restoration targets for various palaeo-ecological research has led to some has new restoration projects underway projects. unique restoration initiatives by the aimed at protecting rare plant species National Tropical Botanical Garden on adapted to dry upland conditions on the At Makauwahi Cave on Kauai’s spectacu- Kauai. For instance, palaeo-botanical island’s leeward slopes. Initial funding of lar Mahaulepu coast, our research group evidence from a cave site a few miles the project in McBryde was made possi- has excavated more than 200 m3 of sedi- from NTBG’s southshore gardens has ble through NTBG Fellows, a major ment from a sinkhole palaeolake in the given scientists their most detailed support group of the organization. centre of the cave system, yielding a evidence yet for how coastal vegetation NTBG’s Limahuli Garden on the north 10,000-year record of changes in sea level, before humans would have looked. As it shore has restored traditional Polynesian environmental conditions and biota. The turns out, the list of species in coastal dry pondfields and other dramatic landscapes fossil-rich mud of this site has yielded forests was quite long and included many through careful attention to the details of about 45 species of fossil birds, for endangered taxa that are represented in local oral traditions and data from adja- instance, as well as more than a dozen the wild today only by a few individuals cent archaeological sites. types of extinct land snails, and a rich at remote inland sites, or that are extinct record of early Polynesian diet and life- on the island but have survived on a A key link in the process of finding the ways. Most germane to the question of neighbouring island. successful path to restoration against the what types of vegetation grew there in the past and could be targets for future restorations, of course, were abundant well-preserved fossil spores and pollen, seeds and fruits, and even leaves, twigs and whole tree trunks. This material showed that, for thousands of years before human arrival, the site was surrounded by a woodland dominated by a small-fruited native loulu palm (Pritchardia cf. aylmer-robinsonii) and a wide array of trees and shrubs. This remarkable vegetation included plenty of kou (Cordia subcordata), a species formerly believed by most botanists to have been brought to the islands by Polynesians. Our radiocarbon dating shows clearly that this tree, as well as hala (Pandanus tectorius), were part of the indigenous flora. ᮤ David A. Burney Volunteers remove invasive grasses and plant native strand plant along the beach at Lawai Kai in the historic Allerton Garden. 46 PLANTTALK 39 January 2005 Armed with this kind of information rainfall area, including evidence for mega- There is a supreme irony in this turn of from the past, NTBG embarked last year tsunamis and flood events. affairs. In order to provide some plants on the ambitious restoration of the spec- with a future, we must look to the past. tacular beach and adjacent coastal forest NTBG has been able to spread this suc- In a sense NTBG’s mission has grown to at Lawai Kai. The project’s first goal was cessful approach, utilizing a deep-time embrace an exciting new concept in to remove the exotic grasses from the perspective to guide ecological restoration conservation – an approach that holds beach strand, which had crowded out efforts, in collaboration with other out the possibility of staving off extinc- most native strand plants and hardened landowners on Kauai. The restoration tion by consulting with the ancestors, the beach’s substrate so that the activities on the 15 acres surrounding the especially those of the plants themselves! Hawaiian green sea turtle or honu Makauwahi Cave was made possible by (Chelonia mydas) had stopped nesting the cooperation of Grove Farm there. Additional challenges were to Company, which leased the land to the create a vegetation barrier to ameliorate research group. Similarly, our 7,000-year National Tropical Botanical Garden the effects of marine overwash (the struc- sediment cores from the Bette Midler is a non-profit institution, dedicated to tures on the site had been damaged Tr ust property in the Kawaihau Wetlands tropical plant conservation and previously by a tsunami and two hurri- on Kauai’s east coast provided a pollen research and to sharing what is canes), while retaining the ocean view. and spore record to guide restoration learned. For more information, please Add to this the need to remove aliens, planning there in cooperation with the visit our website at www.ntbg.org which made up much of the plant bio- Natural Resources Conservation Service http://www.ntbg.org/ or contact us at mass, and create stable habitat for a wide (USDA). Similar collaborations with the (808) 332-7324. array of highly endangered endemic State of Hawaii and US Fish & Wildlife plants, and the order is tall indeed. Service may help in the effort to re-estab- lish rare Hawaiian plant species on ᮢ Nursery Manager Bob Nishek A plan was developed in late 2003 that Lehua, a small islet and seabird colony growing native plants for the Dry addressed these requirements and deliber- just offshore from the nearby island of Forest Restoration Project in NTBG’s ately followed the fossil and historical Niihau. These and other NTBG projects McBryde Garden. Paleoecological evidence to design a vegetative landscape and collaborations may be the best studies of leeward areas of Kauai have aimed at mimicking the kind of plant chance for many rare Hawaiian plant shown that, before their destruction in assemblage that would have been there species to have any sort of future at all. recent centuries, dry forests were about a millennium ago – shortly after remarkably diverse. Polynesian arrival. Evidence from excava- tions at Makauwahi as well as 6000-year sediment cores from Lawai Kai’s own estuary and about a dozen other palaeo- ecological and archaeobotanical sites around Kauai were combined with present and historical records for plants to generate a very long species list. Many of those plants, including rare palms, trees and shrubs endemic to the island, now thrive on the three-acre restoration. Similarly, at Limahuli Garden on the north shore, ancient oral traditions have guided the reconstruction of taro pond- fields in the lowermost parts of the valley. Higher up, a three-man restoration team battles exotic weed trees and plants out hundreds of natives grown in NTBG nurseries. Nearby, a sediment core from a coastal fen contained a 9,000-year record of sedimentation in a windward, high- David A. Burney January 2005 PLANTTALK 39 47.